1. Field of the Invention
The present invention relates to a contact lens insertion apparatus and, in particular, to an improved contact lens insertion apparatus that can be operated easily by anyone, even persons whose muscular control and coordination render it difficult or impossible to insert contact lenses.
2. Prior Art
A variety of contact lens insertion devices utilizing a light source have been designed. Most of these have included a flash light type housing with a lens holder positioned at the top of the housing. A lens may be maintained in the holder in one of a variety of ways, including fluid surface tension, as described in U.S. Pat. No. 3,743,337 to Crary, or suction, as described in U.S. Pat. No. 3,304,113 to Hutchison.
U.S. Pat. No. 3,139,298 to Grabiel teaches a device for inserting contact lenses wherein the lens is retained in a lens holder only by the force of gravity. Thus if the device is tipped to one side or the other the lens will fall off. U.S. Pat. Nos. 3,600,028 to Henning; 3,791,689 to Boone, et al.; 3,934,914 to Carruthers, and the above-identified patent to Hutchison all include means for creating a vacuum to hold a lens in position on a lens holder. Hutchison includes a bulb connected to the holder through pneumatic tubing. The bulb is squeezed and released in order to provide suction or pressure as needed to keep the lens in place or to release the lens. Boone, et al., and Carruthers teach a resiliant pouch surrounding a light path and communicating with a lens holder by way of a hole in the bottom of the lens holder. By squeezing the pouch, a partial vacuum may be created or released for operating the lens holder. Henning teaches another vacuum type arrangement wherein a tube can be pulled upward to create the partial vacuum and pushed downward to release the vacuum. U.S. Pat. No. 4,201,408 to Tressel teaches a similar method of creating a partial vacuum to hold the lens in place. An actuating member may be squeezed to evacuate air from a tube in communication with the lens holder. Tressel also teaches an end piece which can be placed against the cheek of the operator in order to steady the device.
All of the patents utilizing a partial vacuum to hold the lens in position suffer from a common ailment. The lens holder includes a passageway leading to the bulb, pouch, etc. When the suction is created foreign matter may be, and frequently is, drawn into the passageway. This is an especially difficult area to clean, thus providing an environment for the growth of bacteria. In addition, when these devices release the lens, a small burst of air from the bulb, pouch, etc. thrusts some of this foreign matter onto the lens and into the eye of the operator. The net effect of the air passage leading to the lens holder renders these devices less than sanitary.
U.S. Pat. No. 4,093,291 to Shurgin teaches a lens inserter that uses liquid adhesion to hold the lens to the inserter. Shurgin's device also contains a pair of tongs for grasping the side of the lens for removal thereof from the eye.
While most of these designs use illumination to facilitate the proper positioning of the lens on the eye, various methods are used to accomplish the illumination. In particular, the light element may be contained in the housing, as in the Crary and Hutchison patents, or an external light source may be used whereby the illumination is conducted to the lens through either an optical fiber, as in the Boone, et al. patent, or a light pipe, as in the Carruthers patent. Both of these methods provide an illuminated target facilitating the guidance of the lens into the proper position on the eye.
Some of these devices are easier to use than others. Some are in fact quite cumbersome. By way of example, none of the designs provides any means for opening the eyelid while steadying the device for persons who have difficulty holding either their hands or head steady. In addition, the means for providing suction to hold the lens in place frequently requires manipulation of a separate element, such as the squeeze bulb taught by Hutchison. This manipulation may be quite difficult for older people or those having less than full operation of their hands.